A method of observing a three-dimensional image of an examinees eye to be examined, includes: obtaining a first three-dimensional image which is a three-dimensional image of an anterior segment of the examinees eye by optical coherence tomography for obtaining a tomographic image by converging a measurement light on the anterior segment of the examinees eye obtaining a second three-dimensional image which is a three-dimensional image of a fundus of the examinees eye by optical coherence tomography for obtaining a tomographic image by converging the measurement light on the fundus of the examinees eye by a timing different from a timing of obtaining the first three-dimensional image constructing a three-dimensional eyeball image of the examinees eye through image processing based on the obtained first and second three-dimensional images and displaying the constructed three-dimensional eyeball image on a monitor.